Mine prop



y 6 w. L- s. HEUSNER 3,197,244

MINE PROP 7 2 Sheets-Sheet 1 Filed March 26, 1962 J7 .Z' .E' T T July 27, 1965 w. L. s. HEUSNER MINE PROP 2 Sheets-Sheet 2 Filed March 26, 1962 United States Patent Office 3,197,244 Patented July 27, 1965 3,197,244 NIINE PROP Wiihelrn L. G. Heusner, Boehum-Weitmar, Germany, as-

signor to Hermann Sehwarz Kommanditgesellschaft, 'Wattenscheid, Germany Filed Mar. 26, 1962, Ser. No. 182,399 Claims priority, application Germany, Apr. 4, 1961, Sch 29,496 2 Claims. ((31. 28758) The present invention relates to a mine prop with a lower mine prop member and an upper mine prop member in telescopic engagement with each other and adapted to be frictionally held in a desired relative position to each other. More particularly, the invention concerns a mine prop of the above mentioned type with an open clamping collar or clamping ring which engages the outer surface of the upper mine prop member.

It has been suggested heretofore to tighten and relieve the clamping collar of a clamping ring prop by means of a jaw acting as wedge and having a U-shaped cross section, said jaw extending over jaw-shaped ends of the clamping ring. For purposes of tightening and relieving the clamping ring, the jaw is moved parallel to the axis of the prop.

It is an object of the present invention to provide a mine prop with a clamping jaw for actuating the clamping ring, which will make it possible to set all mine props of the same type employed at the same area of operation so that they exert substantially the same supporting force.

It is another object of this invention to provide a mine prop as set forth in the preceding paragraph, which will make it possible considerably to reduce the time for setting and robbing the mine prop.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 illustrates partly in vertical section and partly in view a lock according to the present invention comprising a clamping ring and the clamping jaw means for actuating the latter.

FIG. 2 is a horizontal section through the lock of FIG. 1 as taken along the line 11-11 of FIG. 1.

FIG. 3 is a horizontal section through the lock of FIG. 1 as taken along the line IIIIII of FIG. 1.

The present invention is characterized primarily in that an open clamping ring extends around the upper mine prop member and is supported by the lower mine prop member while the open clamping ring has its two end portions respectively provided with surfaces inclined relative to each other. Tightening means having surfaces inclined corresponding to the surfaces of the clamping ring are provided for engagement therewith, while fluid operable actuating means including means connected to the lower mine prop member are operableto pull the tightening means over the clamping ring in the direction toward the lower mine prop member while the respective inclined surfaces of the tightening means and said clamping ring engage each other. The mine prop structure according to the invention is furthermore provided with abutment means supported by the lower mine proper member and arranged in the path of movement of the tightening means toward the lower mine prop mem bet for limiting the movement of the tightening means toward said lower mine prop member to thereby determine the respective desired maximum clamping pressure to be exerted by said tightening means on said clamping ring and thereby on said upper mine prop member.

Referring now to the drawings in detail, the arrangement shown therein comprises a tubular lower mine prop rnem er 10 which has slidably mounted therein a portion of an-upper mine prop member 11 which latter has a cylindrical outer surface. For purposes of holding said upper mine prop member in a desired position relative to the lower mine prop member, there is provided an open clamping ring or clamping collar 12 resting on a ring 30 on the lower mine prop member 10 and adapted by exertion of pressure on its outer bent-off ends 13 to be pressed against and thus to grip and hold the upper mine prop member 11. ,The free bent-oil ends of the clamping ring 12 form hook-shaped protrusions. The depressions in said hook-shaped ends of the clamping ring are provided with inclined surfaces 14 so that the vertical cross section of this collar portion is wedge-shaped as is clearly evident from FIG. 1. The said inclined surfaces 14 are engaged by correspondingly inclined surfaces 16 forming part of tightening means or a tightening jaw 15 embracing the protruding ends of the clamping ring from opposite sides. The clamping jaw is'arranged symmetrically with regard to the axial plane 32 which passes through the central line of the clamping ring 12 and the longitudinal axis of the mine prop. In this Way, the surfaces 14 of clamping ring 12 bear on the surfaces 16 of the jaw member 15 which surfaces 16 are inclined to correspond with the inclination of the surfaces 14 as is likewise shown in FIG. 1'. The inclination of the surfaces 14 and 16 is such that a self-locking wedge action is producedand that the tightening means 15 will not involuntarily move from its respective adjusted position to another position. This locking action may be made such that the member 15 will not be dislodged when comparatively severe disturbances of the mineral strata occur.

The two lateral wings of the clamping jaw 15 are respectively provided with cylinder chambers 17 having reciprocably mounted therein double acting pistons 18 with sealing rings 33. Each of said pistons 18 is provided with a piston rod 19 which extends through the cylinder bottom 17a fixedly connected to the bottom wall portion of the respective cylinder. The lower end of each of said piston rods 19 has mounted thereon end members 23 for a purpose which will be explained further below. As will be evident from FIGS. 1 and 2, the, cylinder chambers 17 are disposed at opposite sides of the protruding ends of clamping ring 12, and the axes of said cylinder chambers are preferably contained in a plane which also contains the lines along which frictional engagement between the clamping ring ends and the tightening member 15 occurs. This arrangement militates against the generation of undesirable bending moments when the member 15 is moved downwardly over the collar ends in order to tighten the clamping collar.

The end members 23 on the lower ends of the piston rods 19 enter recesses which are vformed in the side portions 21 of a yoke-shaped bearing member 20 connected to the lower mine prop member in any desired manner as for instance byweldin-g and spaced from the upper minefprop member. The end members .23 have a rectangular cross section and are connected to said bearing member 20 by bolts 22. The bearing member 20 is likewise symmetrical with regard to the axial plane 32. The two side portions 21 are interconnected by a plate 24, which latter carries an adjustable set screw 25. The level of the domed end 27 of this set screw is adjustable byscrewing screw 25 into and outof plate 24, a lock nut 26 being provided to hold the screw in its respective adjusted position. The domed end 27 of the set screw 25 serves as stop or abutment to the downward movement of the tightening member 15, the lower surface 34 of said tightening member making contact with the screw end 27.

'The tightening member 15 is so dimensioned that it capable of resisting distortion under the stresses to which it is subjected, especially the bending stresses to which its side portions confining the cylinder spaces 17 are exposed.

The tightening member or tightening jaw 15 is provided with conduit means for conveying fluid to and discharging fluid from the cylinder chambers 17. In the embodiment shown by way of example in the drawings, a fluid pressure medium is adapted to be introduced into the opposite ends'of the cylinder chambers 17 by conduits 28 and 29. Pressure fluid is passed through conduit 28 into the cylinder portions above the pistons 18 when the member 15 is to be moved upwardly to release the collar 12, whereas pressure fluid is introduced into the cylinder chambers 17 below the pistons 18 and above the cylinder bottoms 17a when the member 15 is to be moved downwards to tighten the collar. InFIG. 1, the member 15 has reached its lower end position as determined by the stop or abutment 25. The conduits 28 and 29 lead to a connecting member 31 of any suitable known type through which fluid under pressure from a desired fluid pressure source may be introduced at will to either of the condits 28 and 29. This connection is mounted on the tightening member 15 and is shown diagrammatically in FIG. 2.

For purposes of setting the mine prop, it is first set in any known manner by adjusting the upper mine prop member relative to the lower mine prop member. After the two mine prop members have reached their desired respective position, fluid under pressure is introduced into conduit 29 and thus to the cylinder spaces below pistons 18. As a result thereof, the tightening member 15 will move downwardly and while doing so draws the collar ends together to tighten the collar. The downward movement of member 15 ceases when it contacts the domed end 27 of stop 25 whereupon the admission of pressure fluid is stopped. The fluid in the cylinder chambers 17 at this moment is preferably prevented by any suitable valve means from escaping from the cylinders, even if the pressure supply lead to connection 31 is disconnected. A stop cock may be embodied in the connection 31 for this purpose. This trapping of fluid, especially hydraulic fluid, in the cylinder chambers will assure that even if the self-locking action of the member 15 should accidentally be overcome, the collar or clamping ring will not be released.

Stop 25 may be so designed or arranged as to'move a valve actuating member adapted to stop the supply of pressure fluid to the cylinder piston systems 17, 18 when themember 15 has reached its desired limit or movement. The thus actuated valve may be arranged on member 15 or yoke-shaped bearing member 20 depending on the location of the conduits 28 and 29,

When the clamping ring or collar 12 is to be released, pressure fluidis introduced into conduit 28 and thus to the cylinder chamber portions above the pistons 18 to cause the tightening member 15 to move upwardly on the ends of clamping ring 12. At the same time, any fluid previously trapped in the cylinder chamber portions will be evacuated. The connection 31 may be so arranged that it will be quickly coupled with a fluid supply source through a manually held quick coupling device or piston. This arrangement is particlarly suitable for props that are used individually either as a conventional face support or for example as a chock at a caving edge. Where props embodying the invention are to be used in groups as advancing face supports, the pressure fluid is supplied to the conduits 28 and 29 by hose pipes continuously connected with the prop and supplied through a control valve equipmentdisposed at a suitable station. Such valve equipment could be embodied in a device of any suitable kind for hydraulically setting and releasing and advancing individual props of a group at the appropriate time. Instead of supplying fluid to the cylinder chambers 17 through conduits 28 and 29 in the tightening member .15, the said conduits may be arranged in the bearing member 20 and communicate with conduits formed in the piston rods 19 and the walls of the cylinders.

in practice, the cylinder piston means 17, 18 are so dimensioned and the supply pressure of the fluid pressure medium admitted to said cylinder piston means is sufliciently high as to insure that the tightening member 15 will reach the stop 25' regardless of the condition of the relatively inclined mutually engaging surfaces 14, 16. It will be appreciated that the invention makes the clamping ring tightening operation independent of the ability of the operator setting the prop to judge when the clamping ring has been sufliciently tightened. Thus, the similar advantage present in hydraulic props has been conferred to a friction prop.

The position of the domed end 27 of the stop or abutment 25 is first determined prior to placing the prop into service, in a testing stand by which the load-carrying capacity of the mine prop can be measured with different settings of the stop. The setting may be changed underground as long as the supply pressure of the fluid medium issufliciently high to insure that the member 15 reaches the end of its path.

As will be evident from the above, the invention not only makes it readily possible for all mine props in the same working place in a mine shaft to have the same carrying capacity or for some supports to have a desired capacity diiferent from that of others, but also enables the setting and withdrawal of supports to be eflected comparatively quickly.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawings but also comprises any modifications within the scope of the appended claims. Thus, it is to be understood that the stop or abutment 25 may take forms other than that of a bolt, for example, the form of a wedge, cam or other adjustable elements.

What I claim is:

1. A mine prop having a lower mine prop member and an upper mine prop member arranged in telescopic engagement with and axially adjustable relative to each other, which comprises: an open clamping ring extending around said upper mine prop member and being supported by said lower mine prop member at the top thereof, said open clamping ring having its two end portions respectively provided with surfaces facing away from each other and inclined relative to each other, tightening meanshaving surfaces inclined corresponding to and facing said surfaces of said clamping ring for engagement therewith, pressure fluid operable cylinder piston means having the cylinder means thereof formed in said tightening means and having the piston'means pivotally connected to said lower mine prop member, conduit means in said tightening means for conveying fluid to and discharging fluid from said cylinder means and including connection means for connection with fluid supply and discharge means, said pressure fluid operable cylinder piston means being operable to pull said tightening means downwardly over said clamping ring in the direction toward said lower mine prop member while the respective inclined surfaces of said tightening means and said clamping ring engage each other thereby to close said clamping ring on said upper prop member, and abutment means supported by said lower mine prop member and arranged in the path of movement of said tightening means toward said lower mine prop member for limiting the movement of said tightening means toward said lower mine prop member to thereby determine the respective desired maximum clamping pressure to be exerted'by said tightening means on said clamping ring and thereby to determine the clamping pressure exerted by said clamping ring on said upper mine prop member.

2. A mine prop according to claim 1, in which the tightening means comp-rises two wing portions respectively housing said cylinder piston means and also comprises 5 a bridge section interconnecting said Wing portions and 2,474,062 containing said conduit means and said connection means. 2,750,141 2,953,343 References Cited by the Examiner UNITED STATES PATENTS 5 1,064,007 965,807 7/10 Ga-rvey. 1,541,662 6/25 Robinson 24263.5

6 6/49 Murphy 285421 6/ 56 Tobias. 9/60 Heusner 248-3 54 FOREIGN PATENTS 8/59 Germany.

CARL W. TOMLIN, Primary Examiner. 

1. A MINE PROP HAVING A LOWER MINE PROP MEMBER AND AN UPPER MINE PROP MEMBER ARRANGED IN TELESCOPIC ENGAGEMENT WITH AND AXIALLY ADJUSTABLE RELATIVE TO EACH OTHER, WHICH COMPRISES: AN OPEN CLAMPING RING EXTENDING AOUND SAID UPPER MINE PROP MEMBER AND BEING SUPPORTED BY SAID LOWER MINE PROP MEMBER AT THE TOP THEREOF, SAID OPEN CLAMPING RING HAVING ITS TWO END PORTIONS RESPECTIVELY PROVIDED WITH SURFACES FACING AWAY FROM EACH OTHER AND INCLINED RELATIVE TO EACH OTHER, TIGHTENING MEANS HAVING SURFACES INCLINED CORRESPONDING TO AND FACING SAID SURFACES OF SAID CLAMPING RING FOR ENGAGEENT THEREWITH, PRESSURE FLUID OPERABLE CYLINDER PISTON MEANS HAVING THE CYLINDER MEANS THEREOF FORMED IN SAID TIGHTENING MEANS AND HAVING THE PISTON MEANS PIVOTALLY CONNECTED TO SAID LOWER MINE PROP MEMBER, CONDUIT MEANS IN SAID TIGHTENING MEANS FOR CONVEYING FLUID TO AND DISCHARGING FLUID FOM SAID CYLINDER MEANS AND INCLUDING CONNECTION MEANS FOR CONNECTION WITH FLUID SUPPLY AND DISCHARGE MEANS, SAID PRESSURE FLUID OPERABLE CYLINDER PISTON MEANS BEING OPERABLE TO PULL SAID TIGHTENING MEANS DOWNWARDLY OVER SAID CLAMPING RING IN THE DIRECTION TOWARD SAID LOWER MINE PROP MEMBER WHILE THE RESPECTIVE INCLINED SURFACES OF SAID TIGHTENING MEANS AND SAID CLAMPING RING ENGAGE EACH OTHER THEREBY TO CLOSE SAID CLAMPING RING ON SAID UPPER PROP MEMBER, AND ABUTMENT MEANS SUPPORTED BY SAID LOWER MINE PROP MEMBER AND ARRANGED IN THE PATH OF MOVEMENT OF SAID TIGHTENING MEANS TOWARD SAID LOWER MINE PROP MEMBER FOR LIMITING THE MOVEMENT OF SAID TIGHTENING MEANS TOWARD SAID LOWER MINE PROP MEMBER TO THEREBY DETERMINE THE RESPECTIVE DESIRED MAXIMUM CLAMPING PRESSURE TO BE EXERTED BY SAID TIGHTENING MEANS ON SAID CLAMPING RING AND THEREBY TO DETERMINE THE CLAMPING PRESSURE EXERTED BY SAID CLAMPING RING ON SAID UPPER MINE PROP MEMBER. 